This invention is based on and claims priority to Japanese Patent Application No. Hei 11-361612, filed Dec. 20, 1999, the entire contents of which is hereby expressly incorporated by reference.
1. Field of the Invention
This invention relates to a component mounting arrangement for an engine, and more particularly to an improved mounting arrangement of wire harness and/or one or more fluid conduits for an engine.
2. Description of Related Art
As will be expected, space within any engine compartment generally is at a premium and the wire harness occupies a certain amount of this space.
In addition, the engine normally has external fluid conduits that supply fuel, water and/or oil to appropriate locations of the engine. The external conduits are used because internal fluid passages can be difficult to form. In addition, the space within the block of the engine is often tightly arranged such that passages of adequate size generally cannot be formed within the engine.
In all fields of engine design, there is increasing emphasis on obtaining high performance in output and more effective emission control. This trend has resulted in employing, for example, a multi-cylinder, fuel injected, four-cycle engine. The engine can have multiple cylinders, such as six cylinders arranged in V-configuration.
The engines often require a number of electrical wires for collecting sensor signals to a control device from any of a number of sensors and for sending control signals to actuators from the control device. These wires often are gathered in a bundle referred to as a wire harness. The wire harness for these sensors and actuators is thus likely to be voluminous and makes it difficult to adequately place individual wires around the engine.
The engines often also use external fluid passing conduits. For instance, fuel can be delivered through fuel supply lines formed external to the engine. Of course, other fluids, such as oil and coolant, also are supplied to the engine through external conduits. Thus, it is a serious problem with the engine how the wire harness and fluid conduits are neatly arranged around the engine.
A marine drive such as an outboard motor can of course employ this type of engine. The mounting configuration problem, however, is substantially more serious with an engine for a typical outboard motor because the engine is surrounded by a protective cowling. The protective cowling often is tightly arranged relative to the engine to reduce the overall girth of the outboard motor. Accordingly, the protective cowling generally contains a very limited space in which the wire harness and fluid conduits can be arranged around the engine.
A need therefore exists for an improved component mounting arrangement for an engine that can neatly arrange wire harness or at least one fluid conduit around the engine.
Also, a typical four-cycle engine includes one or more intake and exhaust valves for opening anti closing intake and exhaust ports, respectively, so as to introduce air into the combustion chambers and to discharge exhaust gases from the combustion chambers. A valve cam mechanism that includes intake and exhaust camshafts is provided for actuating the valves. A drive mechanism drives the valve cam mechanism. Typically, the drive mechanism includes a crankshaft and an endless transmitter such as a chain or belt. The crankshaft has a drive sprocket, while the intake and exhaust camshafts have driven sprockets. The endless transmitter is wound around the drive and driven sprockets so that the crankshaft drives the respective camshafts through the endless transmitter.
The typical four-cycle engine for the outboard motor has a crankshaft and camshafts all extending generally vertically. The drive mechanism including the endless transmitter thus is normally located on a top surface of the engine. If the foregoing wire harness and conduits extend over the drive mechanism, the endless transmitter may damage the wire harness or conduits due to inadvertent contact during operation. If, on the other hand, the wire harness and conduits extend below the drive mechanism, the crankshaft and camshafts must be extended an extra length from the top surface of the engine and a relatively large bending moment can exert upon these shafts during operation. The shafts and bearing construction therefore would have to be strengthened.
There can be another arrangement in which the wires and conduits extend on side surfaces of the engine. This arrangement, however, requires relatively long lengths of the wire harness and conduits. Long wires can generate electrical noise in the electrical system and the electrical noise can disrupt operations of the electrical system. Additionally, long conduits can delay delivery of the fluids routed through the conduits. Further, a production cost of the wires and conduits in this arrangement becomes high apparently.
Another need therefore exists for an improved component mounting arrangement that can arrange wire harness and/or one or more fluid conduits on a top surface of an engine where a drive mechanism is provided without damaging wires and/or conduits by a endless transmitter or without requiring to strengthen the crankshaft, camshafts and/or bearing constructions.
In accordance with one aspect of the present invention, an internal combustion engine comprises a cylinder block defining at least one cylinder bore extending generally horizontally. A piston reciprocates within the cylinder bore. A cylinder head assembly closes an end of the cylinder bore to define, together with the cylinder bore and the piston, a combustion chamber. A crankshaft extends generally vertically and coupled with the piston so as to rotate with the reciprocal movement of the piston. An air induction system is arranged to introduce air to the combustion chamber. The cylinder head assembly defines an intake port through which the air is drawn to the combustion chamber. A valve is arranged to selectively open and close the intake port. A valve actuation mechanism is disposed generally opposite to the crankshaft relative to the piston. A drive mechanism is provided through which the crankshaft drives the valve actuation mechanism. The drive mechanism is disposed generally above the cylinder block and the cylinder head assembly. At least one guide member is arranged to guide at least one wire, wire harness or fluid conduit of the engine across and above the drive mechanism.
In accordance with another aspect of the present invention, an internal combustion engine comprises an engine body defining at least one combustion chamber. An air intake passage introduces air to the combustion chamber. A valve is arranged to block the air to be drawn into the combustion chamber when placed in a closed position. A valve actuation mechanism is arranged to actuate the valve from the closed position. The valve actuation mechanism includes a drive unit, an actuation unit actuating the valve, and a transmitter arranged to transmit the driving force of the drive unit to the actuation unit. The transmitter is spaced apart from the engine body by a first distance. At least one groove member is arranged to support a wire harness or a fluid conduit of the engine. The groove member is spaced apart from the engine body by a second distance which is different from the first distance.
In accordance with a further aspect of the present invention, an internal combustion engine comprises a cylinder block defining at least two cylinder bores extending generally horizontally. The cylinder bores are spaced apart from each other so as to form V-configured banks. Pistons reciprocate within the cylinder bores. A pair of cylinder head assemblies closes each end of the cylinder bores to define, together with the cylinder bores and the pistons, combustion chambers. At least the cylinder block and the cylinder head assembly together define an engine body. At least two fuel injectors are provided and each fuel injector is arranged to supply fuel at least one of the combustion chambers. The respective fuel injectors are spaced apart relative to each other. A fuel conduit communicates with the respective fuel injectors. At least one guide member is arranged to guide the fuel conduit. The guide member extends transversely over the engine body.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiment which follows.